This invention relates to an air conditioner, and more particularly to an air conditioner which utilizes air as a cooling or heating medium.
In a conventional air conditioner which employs freon, ammonia, or other refrigerant, the latent heat of vaporization of the refrigerant is utilized to attain heat exchange. According to the closed-cycle operation of such an air conditioner, refrigerant is compressed by a compressor, cooled by a heat exchanger to be liquefied, vaporized by an expansion valve, and again supplied to the compressor.
On the other hand, Japanese Unexamined Patent Application No. S62-102061 discloses another air conditioner which employs air and does not utilize the latent heat of vaporization. In this air conditioner, air is compressed by an compressor, cooled by a heat exchanger, and then adiabatically expanded by an expansion machine for the provision of cooled air.
In the former type of the conditioner, however, freon, ammonia or other refrigerant is released into the air, thereby causing serious atmospheric pollution. The drawback of the latter conditioner is its large size which is inevitable since a great volume of air needs to be circulated and additional components such as a compressor and an expansion machine are required. Additionally, the prior art air conditioners need separate heating and cooling systems and thus become still larger in size in order to effect both heating and cooling of air. Such an air conditioner enabled to both heat and cool air is especially useful when a person in a car is hot at the upper half of the body due to the sunlight through the window and cold at the lower half of the body positioned in the shadow in spring and summer and the independent supplies of cooled air to the upper half and heated air to the lower half are desired, or when heated air should be supplied to a room facing to the north and cooled air to a room facing to the south.